PROPERTY, PLANT, AND EQUIPMENT - Additional Information (Narrative) (Details) - Nuclear Outage	12 Months Ended
	Dec. 31, 2021
Plant Farley | Alabama Power
Property, Plant and Equipment [Line Items]
Regulatory asset amortization period	18 months
Plant Vogtle Units 1 and 2 | Georgia Power
Property, Plant and Equipment [Line Items]
Regulatory asset amortization period	18 months
Plant Hatch Units 1 and 2 | Georgia Power | Maximum
Property, Plant and Equipment [Line Items]
Regulatory asset amortization period	24 months